Philomena Lee, whose young son was sold for adoption by nuns in 1955, has met with Pope Francis in Rome.

Lee, 80, was accompanied by her daughter, Jane Libbteron, and by Steve Coogan, the star, co-writer and producer of Philomena, the Oscar-nominated film based on her case. The contingent were representing The Philomena Project, a campaign which calls on the Irish government to enact legislation to open up adoption records and reunite mothers separated from their children as a result of forced adoption.

They attended mass in St Peter's Square before the audience with the Pope. A screening of the film is expected to take place in the Vatican this afternoon, before a press conference on Thursday morning.

The meeting comes a day after a Vatican spokesman dismissed rumours about such an audience. Said Father Lombardi: "The Holy Father does not see films, and will not be seeing this one. It is also important to avoid using the Pope as part of a marketing strategy."

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Speaking after meeting, Lee said: "I am honoured and delighted to have been in the presence of Pope Francis today. As the film portrays, I have always put great faith in the Church and the good will to put the wrongs of the past right. I hope and believe that his Holiness Pope Francis joins me in the fight to help the thousands of mothers and children who need closure on their own stories."

Lee's son Anthony was three years old when he was sold for adoption to America by nuns at a mother and baby home in Ireland. Both mother and son searched for each other but the nuns who had engineered the adoption tried to prevent a reunion. With the help of the journalist Martin Sixsmith, who wrote a book about the case, Lee was able to find out what happened to her son.

Sixsmith's book, The Lost Child of Philomena Lee, was optioned by Coogan a and subsequently turned into a film starring Judi Dench as Lee and Coogan as Sixsmith. The movie is nominated for four Oscars, including best picture.

Although Philomena as broadly been received as a tribute to faith, controversy has surrounded the film's portrayal of the sisters who sold Lee's child. "We do feel that the film, even though it is not a documentary, does not tell the whole truth and in many ways is very misleading," said Sister Julie Rose of the Sacred Hearts of Jesus and Mary in Roscrea, County Tipperary, where Philomena and Anthony stayed.

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The site protectthepope claims that Coogan "mendaciously blackens the name" of sister Hildegard McNulty, who the film suggests was the chief culprit in keeping apart mother and son.

Philomena has had almost universally warm notices, although one critic, Kyle Smith, wrote an unfavourable review in the New York Post in which he expressed dismay at what he sees as the film's anti-Catholic sentiment, and brands Lee a "ninny". She responded with an open letter in which she defends the film, and hazards that it is a testament to Catholicism that she has retained her faith. She ends by writing: "Just as I forgave the church for what happened with my son, I forgive you for not taking the time to understand my story."